Positive motion fader device

ABSTRACT

Two potentiometers having rotary output shafts are mounted on a support. Each of the output shafts has a substantially cylindrical wheel mounted on it for rotation with the output shaft. The axis of rotation extend in parallelism and are located in a common plane. A first flexible steel strip extends at one side of this plane and has its opposite end portions convoluted in clockwise direction about the one and in counterclockwise direction about the other wheel, the ends of the strip being connected to these wheels. A second similar strip is located at the other side of the plane and has its opposite end portions convoluted in counterclockwise direction about the one and in clockwise direction about the other wheel, also having its ends connected to the wheels. A slider is connected with one of the strips and is guided in a slot so that, when it is shifted along the slot, it causes linear displacement of the flexible strip elements and equal but opposite rotary movement of the wheels and hence of the output shafts of the potentiometers.

Unlted States Patent 1191 1111 3,916,368 Post et al. 5] Oct. 28, 1975 POSITIVE MOTION FADER DEVICE Primary ExaminerVolodymyr Y. Mayewsky [75] Inventors: Herman Post, Great Neck; Attorney, Agent, or Firm--Michael S. Striker George Alexandrovich, Sr., Commack, both of NY. [57] ABSTRACT [73] Assignee: Robins Industries Corporation, TWO Potentiometers having rotary Output shafts are C k NY mounted on a support. Each of the output shafts has a substantially cylindrical wheel mounted on it for rota- [22] Ffled: 1974 tion with the output shaft. The axis of rotation extend [21] Appl. No.: 500,665 in parallelism and are located in a common plane. A first flexible steel strip extends at one side of this plane and has its 0 osite end ortions convoluted in clock- [52] 338/130; 74/665 GE; 338/196 wise directiot n about the one and in counterclockwise hit. CI. direction about the other wheel, the ends of the strip [58] new of Search 338/119 being connected to these wheels. A second similar 338/133 196; 116/124 R; strip is located at the other side of the plane and has 74/665 491 its opposite end portions convoluted in counterclockwise direction about the one and in clockwise direc- [56] References Clted tion about the other wheel; also having its ends con- UNITED STATES PATENTS nected to the wheels. A slider is connected with one of 1,783,542 12/1930 Merle, srj; .1 338/131 h rip nd is gui ed in a slot so that, when it is 2,860,215 11/1958 Williams.... 338/196 X shifted along the slot, it causes linear displacement of 3,185,949 5/1965 Jordan 338/131 the flexible strip elements and equal but opposite ro- 3266326 8/1966 338/131 X tary movement of the wheels and hence of the output 3,390,366 6/1968 lzenour 338/130 shafts of the potentiometers 3,568,113 3/1971 Hopt et al 338/196 X 8 Claims, 2 Drawing Figures U.S. Patent Oct. 28, 1975 3,916,368

BACKGROUND OF THE INVENTION The present invention relates generally to a motiontransmitting mechanism, and more particularly to such a mechanism which is especially useful in controlling a fader for simultaneously varying the strength of two separate electrical signals. I

The invention is applicable to uses other than with fader mechanisms which simultaneously vary the strength of two separate electrical signals, but will be described with reference to such a mechanism hereafter, for purposes of explanation.

Fader mechanisms are multiple-unit controls which are used, for example, in radio for gradual change-over from one microphone or audio channel to the other, in television for changing-over from one television camera to another, and in motion-picture projection for changing over from one projector to another. Their function is, of course, to gradually decrease the strength of one signal, for example, one audio signal, while at the same time, equally gradually and to a concomitant extent increasing the strength of the second signal, for example in the second audio channel. Devices of this type are widely used, especially in recording consoles and broadcasting studios but also in other applications. A single control is used to effect the simultaneous decrease of one signal while effecting the simultaneous increase of the other signal. Fader mechanisms usually use rotary potentiometers having rotary output shafts which must be turned in order to obtain an increase or a decrease-of the respective signal. Conventionally, a pulley arrangement is provided utilizing pulleys on the respective shafts and an associated belt which is trained about the pulleys. This has the disadvantage that slippage may occur between the belt and the pulleys, so that a positive rotation of the two pulleys in unison is not always assured, meaning that the increase in the strength of one signal is not necessarily always precisely equal to the decrease in the other signal, and vice versa. Moreover, and especially if it is desired to operate these mechanisms by converting the linear motion of-a manually shifted slider into rotary motion of the pulleys and hence of the shafts of the potentiometers, the arrangements usually must be relatively large because of the components required to obtain such conversion of motion, and there are frequently difficulties experienced in being able to find sufficient space to install such faders.

SUMMARY OF THE INVENTION Accordingly, it is a general object of the invention to avoid the disadvantages of the prior art.

More particularly, it is an object of the present invention to provide an improved device which affords a positive rotary-to-linear motion and linear-to-rotary motion conversion.

Another object. of the invention is to provide a fader mechanism having the characteristic just mentioned above.

An additional object of the invention is to provide such a fader mechanism which is inexpensive in conometer shaft, from approximately to approximately 270 or more.

In keeping with these objects, and with others which will become apparent hereafter, one feature of the invention resides in a fader for simultaneously varying the strength of two separate electrical signals. Briefly stated, the novel fader comprises a support, a pair of rotary elements mounted on the support for rotary motion about spaced parallel axes, and a pair of flexible strip elements. These strip elements include a first flexible strip element extending between the rotary elements at one side of an axial plane encompassing both of the axes and having one of its end portions trained clockwise about the periphery of one and the other of its end portions trained counterclockwise about the periphery of the other of the rotary elements. A second flexible strip element extends between the rotary elements at an opposite side of the axial plane and has one of its end portions trained counterclockwise about the periphery of the one and the other of its end portions trained clockwise about the periphery of the other rotary element. Connecting means connects the ends of the flexible strip elements to the respective peripheries. Operating means is connected with one of the elements for imparting motion to the same and thereby to all of the other elements.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation illustrating an embodiment of the invention; and

FIG. 2 is a section taken on line IIII of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring in detail to the illustrated embodiment, it will be seen that the invention is disclosed therein on hand of a fader serving to simultaneously vary the strength of two separate electrical signals, for example of two microphone audio channels or the like.

Reference numeral 1 identifies a support in front of a metal chassis which in the illustrated embodiment is of U-shaped configuration, having a transverse wall 2 and a pair of side walls 3, one of which is formed with a longitudinally extending slot 4. Mounted on the wall 2 so as to be stationary are two rotary potentiometers P (one shown in FIG. 2), that is potentiometers which are very well known in the art and which have a rotary output shaft that, depending upon the direction in which it turns, causes an increase or a decrease in the electrical signal passing through the respective potentiometer. The rotary shaft S each carry a wheel 5, 6. These wheels in the illustrated embodiment are made of synthetic plastic material, for instance nylon or the like, and have hubs into which the shafts S extend. Screws 5a, 6a or analogous devices serve to rigidly secure the wheels 5, 6 on the respective shafts S for rotation with the same.

A first elongated strip element 7 is provided, located at one side ofan axial plane passing through the axis of rotation of both of the shafts S and hence of the wheels 5, 6. The opposite end portions of the strip element 7 are trained about the peripheries of wheels 5, 6;-specifically, the in FIG. 1 left-hand end portion is trained in counterclockwise direction about the wheel 5, whereas the right-hand end portion is trained in clockwise direction about the periphery of the wheel 6. The free ends of the element 7 are connected to the peripheries 'of the wheels 5, 6 by means of screws 11 and 12, respectively. Other connecting means could also be used. A second strip element 8 is located at the opposite side of the aforementioned axial plane and also has its end portions trained about peripheries of the wheels 5, 6. However, as far as the strip element 8 is concerned, the in FIG. 1 left-hand end portion is trained in clockwise direction about the periphery of the wheel 5, and the right-hand end portion is trained in counterclockwise direction about the periphery of the wheel 6. In other words, when each of the wheels 5, 6 the end portions of the strip elements 7, 8 are trained about the periphery in mutually opposite directions. The free ends of the strip element 8 are connected to the peripheries of the wheels 5, 6 by means of screws or analogous connecting elements 13, 14.

A bracket is mounted on the wall 2 and a slider 9 having a portion which extends out from the slot 4 is firmly connected with one of the strip elements, in this case the strip element 7. The slider 9 may be injectionmolded onto the strip element 7 or could be secured thereto by means of a rivet, screw or any other suitable means. In any case, the slider 9 may be plastic, or another material can be utilized.

The configuration of the wheels 5, 6 could be different from that which is illustrated; they could be of solid cylindrical configuration or, as is the case in the present instance, they could be of hollow substantially cupshaped cylindrical configuration, to mention just two possibilities. The purpose of the bracket 10 is to serve as a backup for the slider 9 so that the latter cannot be pushed inwardly of the slot 4.

It will be appreciated that when the slider 9 is shifted towards the left or towards the right in FIG. 1, moving in the slot 4, it causes linear motion of the strip elements 7, 8. This linear motion is converted into rotary motion of the two wheels 5, 6 hence of the shafts S of the two potentiometers P. Assuming, for instance, that the slider 9 is moved towards the left in FIG. 1, then the wheel 6 is rotated because it is being pulled by the strip element 7, thus turning in counterclockwise direction. As the wheel '6 turns in this manner, it pulls the strip element 8 which becomes convoluted about the periphery of the wheel 6 to an increasing degree of extent, while becoming unwound from the periphery of the wheel 5, which therefore is caused to turn in counterclockwise direction. The movement of the wheels 5, 6 is therefore in one and the same direction, namely both move counterclockwise. Evidently, if the slider 9 is shifted toward the right in FIG. 1, then both of the wheels 5, 6 will rotate in clockwise direction. By proper adjustment of the wheels 5, 6 and of the strip elements 7, 8 any backlash as it exists in the prior art is eliminated. Due to the fact that relatively large-diameter wheels 5, 6 can be utilized, no sharp bends will develop in the strip elements 7, 8 which might-cause undue friction or even braking of the strip elements 7, 8.

With this construction it is, moreover, possible to obtain a significant increase in the degree of rotation that can be imparted in a linear-to-rotary motion converting mechanism. In the prior-art constructions, utilizing pulleys and belts, only a rotation through degrees could be obtained for the pulleys corresponding to the wheels 5, 6 of the present invention. It is evident from the present disclosure that the degree of rotation is increased by the construction of the present invention to as much as 270 or possibly even more. The device according to the present invention thus affords advantages not found in the art, and provides these advantages in a very simple construction involving a minimum of cost and offering highest reliability. The device is easy to maintain and, because it is inexpensive to construct, is a low-cost assembly that can be readily replaced if and when any of its components do become defective.

No attempt has been made to show electrical circuitry associated with the potentiometers, because faders using potentiometers are very well known, including those using potentiometers having rotary shafts, and in any case the invention resides in the motion transmission between the slider and the wheels 5, 6, and not in the electrical circuitry. The strip elements 8 could be made of a material other than strips of spring steel, for instance nylon tapes or the like. It is one further advantage of the present invention that the potentiometers that are used can be of the type that is completely moisture-proof, and that all of the other components of the device as illustrated in FIGS. 1 and 2, and are not affected by moisture. This is of advantage because in the environment in which faders are usually used, in recording consoles and broadcast studios, one of the recurring problems is spillage of coffee or other drinks, which if it occurs in the prior-art constructions, causes difficulties that are now eliminated with the novel device. It is pointed out that while the present invention is particularly advantageous in connection with a positive-motion fader mechanism, it is by no means limited-to such an application since the rotary-to-linear and linear-to-rotary motion conversion would also be applicable to other constructions. It is also pointed out that if for any reason it should be desirable to transmit motion directly to one of the wheels 5, 6, instead of to .the strip elements by means of the slider 9, which of course is fixedly connected with the element 7 and 7 moves with the same, then an arrangement could be provided which-would turn one or the other of the wheels 5, 6. The transmission of motion would remain the same as described before.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a positive-motion fader mechanism, it'is not intended to be limited to'the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. A fader device a fader for simultaneously varying the strength of two separate electrical signals, comprising a support; a pair of rotary potentiometer elements mounted on said support for rotary motion about spaced parallel axes; a pair of flexible strip elements, including a first flexible strip element extending between said rotary elements at one side of an axial plane encompassing both of said axes, and having one of its end portions trained clockwise about the periphery of one and the other of its end portions trained counterclockwise about the periphery of the other of said rotary elements, and a second flexible strip element extending between said rotary elements at an opposite side of said axial plane and having one of its end portions trained counterclockwise about the periphery of said one and the other of its end portions trained clockwise about the periphery of said other rotary element; connecting means connecting the ends of said flexible strip elements to the respective peripheries; and operating means connected with one of said elements for imparting motion to the same and thereby to all of the other elements.

2. A device as defined in claim 1,

wherein said operating means comprises an operating member connected with one of said strip elements for imparting to the same a linear motion which becomes converted into equal uni-directional rotary motions of said rotary elements.

3. A device as defined in claim 2,

wherein said support has a wall formed with a slot extending longitudinally of said one strip element intermediate said rotary elements; and wherein said operating member is fixedly connected with said one strip element and includes an engaging portion extending through said slot and movable lengthwise of the same.

4. A device as defined in claim 2,

wherein said strip members are strips of spring steel.

5. A device as defined in claim 2,

wherein said connecting means comprises screws.

6. A device as defined in claim 2,

wherein each of said elements comprises a potentiometer stationarily mounted on said support and having a rotary output shaft, and a wheel mounted on and rotatable with said output shaft and having said periphery.

7. A device as defined in claim 6,

wherein said wheels are of synthetic plastic material.

8. A device as defined in claim 6,

wherein said wheels are substantially cylindrical. 

1. A fader device a fader for simultaneously varying the strength of two separate electrical signals, comprising a support; a pair of rotary potentiometer elements mounted on said support for rotary motion about spaced parallel axes; a pair of flexible strip elements, including a first flexible strip element extending between said rotary elements at one side of an axial plane encompassing both of said axes, and having one of its end portions trained clockwise about the periphery of one and the other of itS end portions trained counterclockwise about the periphery of the other of said rotary elements, and a second flexible strip element extending between said rotary elements at an opposite side of said axial plane and having one of its end portions trained counterclockwise about the periphery of said one and the other of its end portions trained clockwise about the periphery of said other rotary element; connecting means connecting the ends of said flexible strip elements to the respective peripheries; and operating means connected with one of said elements for imparting motion to the same and thereby to all of the other elements.
 2. A device as defined in claim 1, wherein said operating means comprises an operating member connected with one of said strip elements for imparting to the same a linear motion which becomes converted into equal uni-directional rotary motions of said rotary elements.
 3. A device as defined in claim 2, wherein said support has a wall formed with a slot extending longitudinally of said one strip element intermediate said rotary elements; and wherein said operating member is fixedly connected with said one strip element and includes an engaging portion extending through said slot and movable lengthwise of the same.
 4. A device as defined in claim 2, wherein said strip members are strips of spring steel.
 5. A device as defined in claim 2, wherein said connecting means comprises screws.
 6. A device as defined in claim 2, wherein each of said elements comprises a potentiometer stationarily mounted on said support and having a rotary output shaft, and a wheel mounted on and rotatable with said output shaft and having said periphery.
 7. A device as defined in claim 6, wherein said wheels are of synthetic plastic material.
 8. A device as defined in claim 6, wherein said wheels are substantially cylindrical. 